1. Field of the Invention
The present invention generally relates to apparatuses for aerating lawns. More particularly, this invention relates to an aerator sulky that is configured for towing behind a selflawn care vehicle, to permit the operator to selectively stand on or walk behind the sulky, and to enable the operator to selectively vary and control the amount of ground engagement of the aerator.
2. Description of the Related Art
Professional lawn maintenance often includes the application of dry and liquid materials including seed, fertilizer, and pesticides, as well as mechanical processes including mowing and aerating. Various vehicles have been developed and are currently in use to accomplish one or more of these common lawn care tasks. For example, commonly-owned U.S. Pat. No. 6,336,600 to Jessen (incorporated herein by reference) discloses a selfcombination fertilizer spreader and sprayer that permits the operator to selectively walk behind or stand on a sulky while traveling at different ground speeds, at least one of which is beyond the maximum comfortable walking speed of a person.
Aeration or aerification is the process of more or less vertically penetrating the thatch and soil with reciprocating or revolving tines to remove thatch and soil plugs. Aerification is very beneficial to the turf in reducing diseases and thatch buildup, relieving soil compaction to increase the root system, and allowing air and water to penetrate into the soil. However, the act of poking thousands of holes in hard soil and removing some of the soil and thatch (particularly in heavy clay soils under drought conditions) is a time-consuming and physically demanding process. It is further complicated by the fact that lawn sizes vary from a few hundred square feet in area up to many acres in size. Consequently, the size, weight, and manueverablity of machinery used to perform these operations are important considerations, especially since heavy machines can compact the soil, further increasing the need for aeration to relieve the compaction. Another burdensome complication is the storage, cost, and maintenance of multiple pieces of equipment, making it highly desirable to have a single machine perform multiple tasks.
Generally, large heavy equipment is required to put enough downward force on aerator tines to penetrate hard soil conditions. U.S. Pat. No. 3,995,564 to Picardat and U.S. Pat. No. 4,424,868 to Staniforth disclose selfaerators on which the operator sits. The disclosed aerators require complicated and costly hydraulically-operated ram systems to transfer enough weight to the aerator tines to penetrate thatch and soil. The aerators are large and heavy, which make operation on smaller lawns with gates, etc., impractical. Furthermore, the aerators disclosed by Picardat and Staniforth are stand-alone machines, and are not adapted for towing behind conventional lawn care vehicles. Even if so modified, these aerators are not adapted for circumstances in which the operator of the unit prefers or is required to walk behind the unit.
An aerator adapted to be retrofitted to an existing selfmower is shown in U.S. Pat. No. 6,241,025 to Meyers et al. The disclosed aerator assembly is pivotably mounted to a mower so that the assembly can pivot from a ground engaged position to a disengaged position by a mechanical or electrical actuator. However, Meyers et al. make no provision to permit the operator to selectively stand on or walk behind the aerator and operate the vehicle as originally intended (e.g., mowing or fertilizing). Furthermore, the disclosed aerator is not configured to allow the operator to selectively vary and control the amount of ground engagement of the aerator tines.
In attempts to overcome the problems associated with operating on small lawns, selfwalk-behind aerators have been proposed, as typified by U.S. Pat. No. 6,102,129 to Classen, U.S. Pat. No. 4,336,760 to Cohen et al., 5,398,769 to Staples, and 4,550,783 to Hansen. While these can be viewed as more compact, lightweight, and maneuverable than other aerating machines, the aerators disclosed in these patents do not provide a place for the operator to stand and ride to reduce the fatigue of walking. Consequently these aerators are not designed to be operated at a speed faster than a person can comfortably walk, which renders the aerators too slow for use on larger properties.
U.S. Pat. No. 6,179,061 to Fiore discloses an aerator sulky that uses the weight of the operator to push the tines into the ground. The aerator is configured so that the operator is required to sit down and stand up to engage and disengage, respectively, the aerator tines. By it""s very nature, aerating hard soils is a jarring and violent process, especially when the tines encounter a subterranean stone or tree root. When sitting, this jarring is transferred directly to the spine, increasing the potential for back injury. Moreover, there is no provision to ensure that the weight necessary for proper tine penetration will be applied.
To provide the weight necessary for proper tine penetration, some aeration equipment are adapted to permit extra weight to be added externally, as disclosed in U.S. Pat. No. 5,020,602 to Dellinger, U.S. Pat. No. 5,579,847 and U.S. Pat. No. 5,623,996 to Postema, and U.S. Pat. No. 5,450,910 to Strzyzewski, or internally within a drum as in U.S. Pat. No. 5,690,179 to Dickson. While effective for the intended purpose, this approach significantly increases the weight of the machine during transport between jobs, requiring the use of heavier and more costly trucks and trailers. To overcome this problem, U.S. Pat. Nos. 5,765,645, 5,579,847, 5,586,604, and 5,623,996 to Postema disclose specially shaped tines that are intended to reduce the weight required for tine penetration. Nonetheless, U.S. Pat. Nos. 5,579,847, 5,523,996, and 5,586,604 also disclose either extra weights incorporated into the aerator assemblies or facilities for adding extra weight. Furthermore, no provisions are made to permit the operator to selectively stand on or walk behind the aerator and operate the vehicle as originally intended (i.e., mowing or fertilizing).
From the above, it can be seen that further improvements in lawn and garden aerators would be desirable. Such improvements would preferably enable the aerating apparatus to be towed by a conventional lawn care vehicle, such as a self-propelled mower or spreader, while permitting the operator to ride or walk behind the vehicle while the vehicle is operated as originally intended (i.e., mowing or fertilizing). It would be further desirable if such an apparatus permitted the operator to stand on or walk behind the sulky while aerating at different forward speeds, including at least one speed that is faster than a comfortable walking pace. It would also be desirable if such an apparatus was configured to allow the operator to selectively vary and control the degree to which the aerating splines engage the ground without resorting to the use of extraneous weights, and without the use of complicated and expensive hydraulic and electrical actuators.
The present invention provides an aerator sulky that can be towed by a selflawn vehicle, such as a mower or fertilizer spreader. The sulky is particularly suitable for attaching to a self-propelled lawn vehicle that can operate at a relatively high speed, during which time the operator rides the sulky, and at a relatively low speed when the operator is able to walk behind the sulky.
The aerator sulky of this invention generally includes a frame having a front portion and oppositelyside portions, wheels mounted to support the frame, and means for pivotably connecting the sulky to a towing vehicle. A first platform is mounted to the frame for supporting an operator of the sulky while in a standing position. The first platform is located on the frame to enable the operator to step forward onto the first platform to ride the sulky and to step rearward off of the first platform to walk behind the sulky. A second platform is pivotably attached to the frame and configured to enable the operator to stand thereon while performing an aerating operation with the sulky. The second platform is further configured to enable the operator to step forward onto the second platform to ride the sulky, step rearward off of the second platform to walk behind the sulky, and step to and from the first and second platforms. The second platform is pivotably attached to the frame so as to enable the operator to shift his/her weight in order to selectively raise and lower the second platform between a ground-engaged position and a ground-disengaged position. At least one aerator tine assembly is rotatably mounted to and beneath the second platform so as to engage the surface beneath the sulky when the second platform is in the ground-engaged position and to be out of contact with the surface beneath the sulky when the second platform is in the ground-disengaged position. The sulky further comprises means for affecting motion of the second platform between the ground-engaged and ground-disengaged positions thereof.
In view of the above, it can be appreciated that the aerator sulky of this invention is configured to enable an operator to selectively vary and control the position of the aerator tines by using his/her weight to force the tines into the soil without complicated and expensive operating devices and without installing additional weight. In a preferred embodiment, the sulky is suitable for attachment to a self-propelled lawn vehicle, such as a mower or spreader, and can be used to perform aeration while the operator is standing on the sulky and traveling at a relatively high speed, as well as perform aeration while the operator is walking behind the sulky at a relatively low speed. The sulky also permits the lawn vehicle to be operated at any speed without performing an aerating operation.
Other objects and advantages of this invention will be better appreciated from the following detailed description.